chapter 3 Flashcards
genetics
the science that allows one to study how traits are passed from parent to offspring
father of genetics
Gregor Mendel
Autosomes
all chromosomes other than sex chromosomes
sex chromosomes
X or Y chromosomes
Filial generation
the offspring from a mating
genotype
the genetic makeup of the offspring
phenotype
physical appearance of the offspring
true breeding
cross between homozygous dominant or recessive traits (cant be heterozygous)
incomplete dominance
a dominant allele cant mask the expression of another allele
co-dominance
two dominant alleles are going to be expressed
sex linked genes
genes that are found on the X or Y chromosome
a sex linked gene will be expressed in….
males
karyote
a preparation of an individuals metaphase chromosome’s
pedigree analysis
study of a family tree, can be used to determine whether a trait is dominant or recessive
inversion
occurs by a breakage in chromosome & it rotates 180 degrees then re-attaches, NO imbalance of genetic information & not identifiable under microscope
two types of inversion
paracentric
pericentric
paracentric
occurs outside of the centromere
pericentric
inversion that involves or spans the centromere
translocation
occurs when two non-homologous chromosomes mutate by exchanging parts, can alter size of chromosomes & position of centromere, identifiable under microscope
nondisjunction
failure of chromosomes or chromatids to separate during meiosis
DNA is composed of
sugar, deoxyribose, a phosphate group & the nitrogen bases
Adenine & Guanine
double ring structure called purine
Cytosine & Thymine
single ring structures called pyrimidine
backbone of DNA consists of
sugar & a phosphate group
rungs in DNA are the nitrogen bases..
purine & pyrimidines
primary structure
DNA in helical form. it establishes a hydrophilic & hydrophobic region
backbone region is…
hydrophillic
runs of DNA is…
hydrophobic
DNA is found in
mitochondria & or nucleus
secondary structure of DNA
unzipped DNA looks like a ladder & it establishes polarity
Griffiths experiment
showed that DNA is the genetic information
Hershey & Chase experiment
showed that DNA is the genetic information
semi conservative replication
each strand of a DNA molecule is used to make a new strand of DNA
leading strand
strand of DNA where replication is continuous
lagging strand
strand of DNA where replication is discontinuous
okazaki fragments
fragments of DNA found on the lagging strand
RNA primers
short stretches of RNA which are headed to jumpstart DNA replication
Criteria for DNA replication:
only occurs in single stranded DNA, only occurs in one direction 5-3, bidirectional
players for DNA replication
single stranded binding proteins
DNAa proteins
single stranded binding proteins
bind to single stranded DNA & prevent from rezipping
anaplasia
the reversion of cells to a simpler or less differentiated form
neoplasm
a tumor or tissue containing abnormal growth
malignant tumor
invades tissue, spreads across body, life threatening
3 types of cancer
carcinoma, sarcoma, adenoma
carcinoma
malignant tumor starts in the surface layer of an organ & may spread to other parts of body
sarcoma
malignant tumor found in connective tissue like muscles, bone & blood
adenoma
a benign tumor in glandular tissue
causes of cancer
environmental factors: UV radiation, preservatives, viruses, carcinogens
causes of familial cancer
damages to DNA
loss of growth control mechanisms
proto-oncogenes
normal genes that have the capacity to become cancerous genes
oncogenes
genes that accelerate cell growth. mutated proto-oncogenes. if not activated correctly it can lead to cancer development
tumor suppressor genes
stops the replication of a cancer cell
checkpoints
points in the cell cycle where cell is checked for a product, each stage of the cell cycle has a checkpoint, cancer develops when theres a problem w/ a checkpoint
sporadic cancer (non-hereditary)
cancer that doesn’t appear to be inherited
DNAa protein
bind to the orgin of replication & help to start replication
Helicase
unzips the DNA molecules
Toposiomerase
relieve supercoiling of the DNA molecule
DNA poly 1
makes the chain & corrects mistakes
DNA poly 2
function is unknown
DNA poly 3
main enzyme in DNA replication
ligase
(glue) enzyme is responsible for joining DNA fragments together
RNA primase
enzyme which synthesizes the RNA primer
DNA replication
process where DNA is copied
where does DNA replication occur
in the nucleus of the cells
Actions of the chromosome
begins to unzip & the DNAa protein attaches to the orgin of replication
SSBP bind to unzip DNA
In replication
the strand begins to unzip by helicase, then the single stranded binding proteins bind to single stranded DNA, ends in removal of SSBP & two DNA molecules rezip
transcription
the synthesis of an RNA strand using a DNA template
RNA serves as a connector between
DNA & Protein
sugar in RNA is
ribose
mRNA
messenger RNA, makes the amino acid sequence of the protein
tRNA
transfer RNA, brings amino acids to ribosomes during translation
rRNA
ribosomal RNA, helps to form a functional ribosome
transcription uses which strand of the DNA template?
3–>5 strand
transcription uses uracil instead of
thyamine
promoters
sequences of DNA that attract RNA polymerase to that site for transcription to occur
-35 region
a CG or GC region that is located 35 nucleotides before the start site of transcription
-10 region
located 10 nucleotides before the start site
RNA polymerase
a multi-sub unit enzyme that is composed of 5 subunits
step 1 of transcription- initiation
requires that the RNA polymerase holoenzyme binds to the correct promoter DNA sequence, causes DNA to unzip
step 2 of transcription- elongation
RNA synthesis begins
step 3 of transcription- termination
terminator sequences are used to end transcription
2 types of termination
rho independent termination
rho dependent termination
rho independent termination
formation of a hair pin loop
rho dependent termination
a protein called rho binds to DNA & physically blocks the enzyme
splicing
removal of non-coding RNA
introns
the RNA sequences that are removed from the message
exons
the RNA sequences that are expressed or converted into proteins
translation
process where mRNA is converted into proteins, occurs in the cytoplasm on ribosomes in the RER
what is needed for translation?
ribosomes, rRNA, tRNA, & amino acids
in translation, rRNA is responsible for
combining the small & large subunits of the ribosome together
in translation, tRNA is responsible for
bringing the amino acids to the ribosomes. there are 20 known
amino acids are
monomers of proteins
3 steps of translation
make a functional ribosome, AUG binds to the P site, bind to the A site
